Philippine security forces on Saturday announced control over the province of Maguindanao hours after martial law was declared and nine people, including top provincial officials, allegedly linked to last week' s massacre, were held in custody.

"We are here this morning at the capital to announce that martial law proclamation. We are to take over the capital. All municipal halls will be secured by the army," Eastern Mindanao Command chief Lt. Gen. Raymundo Ferrer.

Speaking with reporters, Ferrer said there was no appointment yet as martial law administrator but by virtue of the highest military commander, soldiers came here to formally take over the capital while waiting for further orders.

"The focus is to conduct arrest and searches of the houses or premises of suspected perpetrators of Maguindanao massacre. We are looking for 100 men involved in the crime and what we have are those chief executive who were part of the conspiracy," the military official added.

Philippine President Gloria Macapagal-Arroyo on late Friday imposed martial law in Maguindanao to smooth the arrest of suspects behind the massacre of 57 civilians on Nov. 23.

Nine people being held custody on Saturday include most of the Ampatuan clan who has ruled the province since 2001, headed by three-term governor of Maguindanao and clan patriarch Andal Ampatuan Sr., Governor of the Autunomous Region of Muslim Mindanao Zaldy Ampatuan, current Maguindanao Governor Sajid Ampatuan, regional military officials said.

Justice Secretary Agnes Devanadera said the nine can only be detained for three days without formal charges filed against them in court.

The Ampatuans are suspected of ordering the massacre of at least 57 unarmed civilians, including 22 women, who were on an election caravan to witness one of the family's political rival to be registered as governor candidate in next year's election.

Authorities have arrested and charged Andal Ampatuan Jr., mayor of Datu Unsay town of Maguindanao, as the prime suspect in the massacre. Thousands of troops moved in Maguindanao since last week and the authorities have ordered the relief of over 1,000 local law enforcement personnel and started to disarm Ampatuan family's private armies.